On 21 December, 2010, the Daily Telegraph splashed with revelations based on secretly taping Cable during a constituency surgery.

The story omitted the most newsworthy element of the story – that Cable said that he had ‘declared war on Rupert Murdoch”. The Telegraph later said that it was merely planning to run this revelation as a follow-up.

The omission led to an unknown source accessing the full transcript via the Telegraph’s content management system and leaking it – via an intermediary – to the BBC’s Robert Peston. The revelation of the full comments on Peston’s blog that day led to Cable losing responsibility for deciding on Murdoch’s proposed bid for BSkyB – an outcome which could be said to be against the Telegraph’s commercial interests.

Telegraph Media Group had declared its opposition to Murdoch’s News Corp acquiring BSkyB.

Counsel for the Leveson inquiry Robert Jay QC asked Lewis if he was the source who had leaked the full transcript to Robert Peston. Former Telegraph editor Lewis was at this time working for News International as general manager.

Lewis said: ‘I can’t assist you with that. As you know core to any journalist is the protection of journalistic sources, my sources or someone elses. Any way that I answer that question would endanger that principle.”

Lewis said that if he was to say that he wasn’t the source, it could lead the Telegraph to try to ‘hunt down’another potential source.

When pressed again by Jay, Lewis said: ‘Clause 14 of the PCC code is as much about protecting my own sources as protecting other journalists’ sourcesâ€¦In this instance I have gone as far as I could and should.”